Abstract：Asymmetric zeolite NaA membrane layers are synthesized on tubular α-Al2O3 supports by the vapor phase transfer method followed by seeded growth. The preparation of the asymmetric zeolite NaA membrane layer includes the preparation of porous zeolite NaA membrane sublayer by vapor phase transfer method and the preparation of dense top layer by seeded growth. The effects of the Na2O/Al2O3 ratio, pretreatment time and water content of the hydrogel, as well as the vapor phase transfer time on properties of porous zeolite NaA membranes are investigated. The optimal conditions of the hydrogel are as follows: pretreatment temperature 50 ℃, pretreatment time 5 h, and the composition of the hydrogel 7.5Na2O:2SiO2:Al2O3:150H2O. The seeds of 120 nm are coated on the porous zeolite NaA membrane by wetting-rubbing. Asymmetric zeolite NaA membrane layers are synthesized with the secondary growth method from the seeded membranes. Zeolite NaA membranes are characterized by SEM and pervaporation separation of 90% ethanol aqueous solution at 75 ℃. The flux of the membrane is up to 3.43 kg/(m2·h), while the separation factor is 3 685.
Ma Jie,Shao Jia,Wang Zhengbao. Preparation of Asymmetric Zeolite NaA Membrane Layers by Vapor Phase Transfer and Seeded Growth Method[J]. 化学反应工程与工艺, 2015, 31(1): 26-32.
